package org.example.springboot3.mapper;

import org.example.springboot3.domain.Registrations;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;

import java.util.List;

/**
* @author xu264
* @description 针对表【registrations】的数据库操作Mapper
* @createDate 2025-05-26 13:27:54
* @Entity org.example.springboot3.domain.Registrations
*/
public interface RegistrationsMapper extends BaseMapper<Registrations> {
    List<String> getMyActivityList(String id);//通过用户id查询当前用户参与活动的ID列表
    String getParticipantNum(String id);//通过活动id查询当前活动的参与人数
    int exitActivity(String userId,String activityId);//删除当前用户的活动参与记录
    int deleteByActivityId(String activityId);//删除所有该活动id的参与记录
}




